<section data-type="foreword">
  <h1>Foreword</h1>
  <p>It’s fun to be a science fiction writer. To build a society where wealth is no longer a mirage erected on the empty promises of governments and manipulations of central banks, where exchanges of value can be completed among the trustless without paying a tax to middlemen, where code can be law, where collective decision making is not subject to the distortions of centralization&#x2026;all I have to do is to open up a text editor and start making up stuff.</p>
  
<p>But compelling stories require more than imagination. They require knowledge of the world. “Worldbuilding” isn’t about literary verisimilitude or strings of technobabble—it’s about piercing through the superficial to ask “what if” questions that get at the heart of how the world works. The more a writer understands the mechanisms and codes that make up the world, the more interesting the questions they ask become.</p>

<p>Changing the real world is much, much harder than writing fiction, but it similarly requires knowledge. Beyond wisdom, idealism, grit, discipline, and single-minded determination in the face of doubt, a would-be world-changer needs understanding: of the available tools, their capabilities, and their limits. </p>

<p>The world of Bitcoin and blockchain today is still largely a world of fiction. Pundits selling hope and hype, with no understanding of the underlying reality, are far louder and more influential than those who are doing the hard work of bringing about change. Politically motivated screeds premised on fear and get-rich-quick schemes appealing to greed pass for knowledge with the help of a sprinkling of technobabble and trending hashtags. </p>

<p>But you can no more understand blockchain by reading whitepapers or thinkpieces than you can learn to build a company by going to business school and watching PowerPoints. </p>

<p>You have to code.</p> 

<p>There is no better way to understand a technology than to build something useful to you in it. Until you’ve coded the fundamental building blocks of a blockchain application with your own hands, you will not be able to intuit the difference between empty hype and realizable possibility.</p>

<p>This book is the most efficient and comprehensive way to learn about Bitcoin and blockchain through coding. With great skill and insight, Jimmy Song has crafted a learning path that will take you from the basic math behind Bitcoin to the latest extensions and forks. Along the way, the exercises—refined through extensive work with live students—will not only teach you the mechanics of working with the blockchain, but also an intuition for the elegance and beauty of this technology.</p>

<p>The journey will not be easy. Even with a teacher as adept as Jimmy to guide you, this isn’t a book to be flipped through when you’re bored from bingeing on Netflix. It requires you to put in considerable work to get the most out of it. There is no shortcut, no CliffsNotes. But that is very much in line with the constitutive principle of Bitcoin: you must have skin in the game; you must demonstrate proof-of-work. Only then can you trust your knowledge.</p>

<p>Happy coding!</p>
<p class="byline">Ken Liu</p>

<p>&nbsp;</p>

<p><em>A winner of the Nebula, Hugo, and World Fantasy awards, <a href='http://kenliu.name'>Ken Liu</a> is the author of</em> The Dandelion Dynasty<em>, a silkpunk epic fantasy series in which the magic is engineering, and </em>The Paper Menagerie and Other Stories<em>, a collection. His SF story about blockchain, <a href='https://breakermag.com/kchain-science-fiction-premiere-byzantine-empathy/'>“Byzantine Empathy”</a>, was originally published by the MIT Press.</em></p>
  
  
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